Smokers trying to kick the habit might stand a better chance of staying smoke-free if they begin using replacement nicotine patches or gum in the weeks before they quit cigarettes.

That's a theory a team led by the Clinical Trials Research Unit (CTRU) at The University of Auckland's School of Population Health is testing in a study funded by the Health Research Council and National Heart Foundation.

Principal investigator Dr Chris Bullen says the conventional wisdom is that people trying to quit throw away their cigarettes and immediately replace them with a nicotine substitute, such as nicotine patches or chewing gum.

But some recent small-scale studies have suggested that the earlier use of a nicotine substitute might improve the chances of a person staying smoke-free.

"It's been suggested that if a smoker starts using nicotine substitutes about a fortnight before quitting cigarettes, they are significantly more likely to remain smoke-free six months later.

"We want to test this idea in a properly controlled, randomised trial."

Researchers from The University of Auckland together with colleagues in The Quit Group and the University of Otago will work with 1100 people, enlisted through the national Quitline. Half the participants will be offered nicotine patches or gum two weeks before they attempt to quit; the other half will begin using the patches or gum on the day that they quit.

"Using nicotine gum or patches while still smoking is very safe," said Dr Bullen. "We will track how study participants respond in the days immediately after they quit. And we will continue to monitor them through to the six-month milestone, which is regarded as a critical make-or-break date when assessing quitting success."

Findings from the research will provide useful information about more effective use of nicotine patches and gum for people who want to quit smoking, estimated to number about 430,000 people in New Zealand alone.

There are several theories as to why early use of nicotine replacements might assist in breaking the cigarette habit, according to Dr Bullen.

"Nicotine is a highly addictive substance. It has been proposed that the stress a person undergoes when giving up cigarettes, coupled with the burden of remembering to use alternative methods of nicotine delivery, is too much too soon.

"If a person first becomes used to the patch or gum, it might make the transition to being smoke-free easier because a crucial part of their behaviour has already changed.

"Another theory is that the combination of cigarettes with an additional source of nicotine 'saturates' the brain nicotine receptors. Individuals might lose some of their desire for cigarettes before trying to completely give them up.

"These are largely untested ideas. The aim of our research is to discover if there is a measurable difference in quitting success rates between the two groups in our trial," said Dr Bullen.